Electrically operated brakes have been developed and used on vehicles for a period of time. A desirable characteristic offered by such brakes reside in their simplicity and an opportunity to reduce the overall weight of a vehicle. Examples of such brakes can be found in the following U.S. Pat. Nos. 4,793,447; 4,804,073; 4,850,459; 4,928,543; 4,944,372; 5,201387 and 5,913,390.
In these brakes, an output torque from an electric motor is modified through the use of various gears to provide an input for moving brake pads into engagement with another member to effect a brake application. An individual brake module for a vehicle would include a drum brake in which first and second brake shoes are urged by an actuator as a function of torque developed by an electric motor in response to an input signal supplied by a controller by an operator to effect a brake application. A concern in the operation of such brakes is the speed at which the actuation force develops and the intensity of the resulting actuation force is produced to bring the vehicle to a stop within a desired braking distance during a brake application In vehicles having electric brakes sensors are associated with the individual wheels to supply a controller with an indication of the braking of each wheel in order to regulate the individual wheel operational signals to achieve a smooth, balanced and effective stop. Unfortunately servo action which occurs between a leading brake shoe into the trailing brake shoe and variations in brake effectiveness may erroneously influence the brake torque generated during braking. Thus, while electrically operated brake systems meet current standards of operation their use has generally been limited to use in brake systems for towed vehicles